Material working apparatus and hydraulic system of control therefor



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E. J. svENsoN 2,078,698

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April 27, 1937. E. J. svENsoN MATERIAL WORKING APPARATUS ND HYDRAULIC SYSTEM OF CONTROL THEREFOR Original Filed Nov. 1, 1933 l0 Sheets-Sheet 9 v April 27, 1937- E. J. svENsoN 2,078,698

MATERIAL WORKING APPARATUS AND HYDRAULCy SYSTEM`OF CONTROL THEREFOR y Original Filled NOV. l, 1933 10 Sheets-Sheet l0 mmh MATERIAL WORKING APPARATUS AND HYDRAULIC SYSTEM F CONTROL THEREFOR Ernest J Svenson, Rockford, Ill.

Application November 1, 1933, Serial No. 696,284 Renewed August 10, 1936 61 claims.

invention relates generally to material working apparatus and hydraulic systems of control therefor, and more particularly to machine tools and improved hydraulic systems for controlling the timed functioning of machine tools.

The use of hydraulic mechanisms for propelling machine tools and the like has, during recent years, been given considerable attention by machine tool designers and builders.

knowledge, it has been the practice heretofore in many instances to apply hydraulic systems of control to a machine tool without giving suincient preliminary consideration as to whether or not the control system selected was particularly suitable for the structural environment presented by the machine tool per se. It is my belief that one of the most diiilcult problems confronting those particularly interested in the art of machine tool design, is that of supplying a hy- 20 draulic system of propulsion or control, which is suitable for the particular environment in which it 2is to operatively function. In order to'obtain the maximum benefit or usefulness of the hydraulic-system of propulsion, it is essential that l' 25 the structural features forming a part thereof be designed with the utmost precision. It is, therefore, one of the important objects of the 'present invention to provide simple and highly eiilcient hydraulic actuator systems, which are arranged Ato satisfy all of the working conditions of the machine tool with which they are to be y employed.4

More particularly, my invention contemplates a machine tool and a system' of control 'therefor, Awherein the proper timed functioning of a Chydraulic actuator for propelling a machine part may be controlled more accurately and positively. Another object of the present invention is to 'provide a hydraulicpropulsion and control ar- 40 rangement which is particularly adaptable for use with machine tools designed to perform varied and successive operations upon a work piece.A

A further object of my invention is to provide in systems of the above mentioned type improved mechanismfor obtaining a. predetermined dwell 'of an actuator-at any desired interval in the cycle of operation.

Still` another object 'of the present invention' is to provide an improved control arrangement '5o wherein a plurality of feeding speeds may be imparted to a machine part in response to the actuation of a simple unitary control mechanism, v. `which is lfree-from conventional load and nre -`spring arrangements, and dependsv solely upon 'p5 hydraulic power for a control device.

"(01. ca -3s) More specifically, the invention contemplates the 'use of two feed pumps', one to be used for slow feeding purposes, and the two combined to be used for increased speed, the functioning of. said pumps' being controlled through the agency of a simple unitary control mechanism. 5

Still more specifically, the invention contemplates a hydraulic control mechanism for the multi-speed feeding arrangement set forth above wherein a control element is adaptedto be lo shifted to at least two different positions without the aid of auxiliary spring devices and the like, and in each of the positions said control element performs a predetermined function'in selectively controlling the delivery of uid from the pumps to an actuator.

In carrying out the foregoing object, I propose to employ a main valve, and a. control elementl which is operable in response to the shifting of said main valve to thereby selectively control the voperative functioning of the pumps.

It is a further object of the invention to provide the two-speed feeding arrangement employing a plurality of pumps in combination with means such as another pump adapted to deliver iiuid to the actuator for rapid traverse purposes, 25 and under such circumstances, a main operating valve serves to control thedelivery of uid from said rapid traverse pump to the actuator.

Another object is to enable the use of a plurality of constantly driven feed pumps in combination with meansfoxj selectively controlling the delivery of iiuid from said pumps to an actuator without disconnecting said pumps from their'` prime movers. i

Another object of my invention yis to providean improved self-contained pump unit, which includes a unitary frame providing a support for at least two feed pumps, a rapid traverse pump .and a fluid reservoir. f 1

The present invention also contemplates an improved hydraulic system of control wherein a series arrangement is provided to enable the movement of oneactuator to be controlled in response to the uid delivered from the discharge side, of another actuator in combination withV improved means for controlling the timed functioning of said actuators.

' My invention also contemplates the provision of an improved system o hydraulic `control wherein a plurality of mais r actuators are4 employed to control .the operative. functioning of a plurality of actuators adapted to move machine parts and the like.

A further object is to provide in a machine tool of the axis of a rotarywork support, va single actuator being adapted to simultaneously cause the shifting of both tool supports, and thereby vsimultaneously aiect the. positioning of vsup-` ported tools with respect to a work piece.

The'foregoing and numerous other objects and advantages will be more apparent from the fol--y lowing detailed description when considered in connection with the accompanying drawings, wherein Figure 1 is a fragmentary side elevational view of a boring machine which is representative of one machine adapted to be equipped with my improved system of control;

Figure 2 is an enlarged fragmentary view of the central portion of the machine shown in Figure i to more clearly illustrate the position of the circuit control mechanisms and the dogs cooperatively arranged therewith;

Figure 3 is a fragmentary transverse sectional view taken substantially along the line 3 3 of Figure 2;

Figure 4 is a fragmentary plan sectional view of the dogs and valve actuating iingers, said View being taken substantially along the line @-4 of Figure 2;

Figure 5 is a fragmentary when desired in combination with the circuit of' Figure rI;

VFigure 9 discloses a hydraulic circuit arrangement coupled with machine elements to disclose the manner in which an indexing mechanism is hydraulically controlled in timed relation with.

the movements of the spindle supporting heads; Figure 10 is a circuit diagram of a modified hydraulic control 'arrangement' wherein two feed work support 40. A detailed description of the head and work support is not essential to an pumps are employed incombination with means for selectively controlling thefunctioning thereof; l I y/ Figure 11 discloses the feed pump control element shifted to its rst position which it occupies when the main control valve is shifted slightly toward its reverse position;

Figure 12 discloses the position occupied by the --fed pump control element when the main control valve occupies its reverse position;

Figure 13 discloses the position occupied by the feed pump control element when the main valvehas been shifted to its rapid approach position;

Figure 14. discloses' the position occupied by the feed'pump control element when the main control valve has been shifted from the reverse position to its neutralv position;

Figure 15 disclosesvthe pump unit particularly adapted for use in connection with machine tools employing a hydraulic system of control' which uses the two-speed feeding arrangement,

a portion of-thel unit being shown in section in order to more clearly illustrate the intern-al arrangement thereof; I

geraete transverse vertical sectional view taken substantially along the line Figure 16 is a fragmentary view of the pump unit as viewed from the right of Figure 15;

Figure 17'is an enlarged fragmentary sectional view of the ball valve arrangement'in the pump disclosed in Figure 15; y

Figure 18 discloses a modified hydraulic actuator control with atWo-speed feeding arrangement and means for hydraulically controlling the radial movement of cutting tools carried by a spindle head;

Figure 19 is a modified hydraulic control cirsuit employing a series actuator construction;

Figure 20 is, still another circuit arrangement wherein master cylinders are employed to control the functioning of actuators designed to propel machine parts and the like;

Figure 21 is a transverse sectional view of va lmachine tool equipped with a single actuator wherein the control valve may be unbalanced in either direction.

Referring now to the drawings more in detail wherein like numerals haveA been employed to designate similar parts throughout the various figures, it will be seen that for 'thepurpose of illustrating the practical application of my improved systems of hydraulic propulsion, I have shown the same in operative association with a material 'working apparatus or boring machine designated generally bythe numeral 30 (Figure l). 'vI'his apparatus or machine includes an elongated base or bed 32, which is provided along its upper surface with guides 34.

`Reciprocably mounted upon the guides 34 is a head 36. In the drawings I have disclosed a fragmentary portion of themachine, and it will be understood that in a complete machine' a head, similar to the vhead 36, is positioned op'- positively to the head 36 and is reciprocable upon the guides .34. For a clear understanding of the present invention,l the disclosure of a single head or unit 36 will sufi'lce. To the right of the head 36 I indicate fragmentarily a Work holding mechanism 38, which includes an indexable understanding of the invention, and I do not chine is designed to perform a series of operations upon work pieces supported in the vindexable work holder. A-prime 'mover or electric motor 42 is arranged to impart rotation to the plurality of .tool spindles projecting from the vright end of the head 315, as`clear1y shown in Figure 1. A suitable feed'pump 44 is also driven 'from the prime mover 42, and positioned immediately beneath the head 36 is a hydraulic actuat'or 46, which includes a cylinder 48 secured as 'a unit to the bottom side of the head 36 andal piston 50 connected witha piston rod A52, which is secured at vits left end vto 'the base or bed 32.

It will thus be apparent that iluid introduced within the right end of the cylinder 48 will cause the head to move to the right, and uid introduced within the left end of the cylinder 48 will cause the head to move to the left.

The feed pump 44 is preferably of the type shown more specically in Figures 15 and 16, later to be described. It will suiiice to say that I prefer to employ a feed pump which is free from uid slippage, namely, the slippage or leakage of uid from the high to the low pressure side. As a further example of a type of pump which may be employed, I make reference to the pump disclosed in my copending application, Serial No. 430,867, led February 21, 1930, which has now matured into Patent No. 1,989,117.

A main valve or control mechanism 54 is sey cured to the front side of the head frame 36, as

clearly indicated in Figures 1 to 3, inclusive. This Valve mechanism includes a valve member 56 (Figure 7) which is shiftable within a valve -casing 58 through the agency of a manually 'operable lever or handle 60. This handle 60 is secured to a vertical shaft 62, the lower end of which carries a pair of fingers 64 and 66 adapted to be actuated by companion dogs 68 and 10, respectively, (Figure 4). These dogs are adjust- ,ably supported by a bar 12, and, as the head moves along the guides 34, these dogs operate to timingly control the shifting of the vvalve member 56, as will later appear. The functioning of the valve mechanism 54 and other mechanisms included within the circuit shown in Figure 7 will be best understood from a statement of operation. 56 occupies the central or neutral position shown in Figure 7, and that the feed pump 44 and a 'rapid traverse pump 14 are being operated by .derstood that in the actual construction of Vthe valve, this conduit is enclosed lwithin the valve y housing, but, for the purpose of simplifying the disclosure, said passage is shown diagrammatically in Figure 7. Fluidfrom the chamber 88 passes through a conduit 92, which returns iud Y to the reservoir 16 through a xed 'restricted oriiice 94. Thus, when the valve member 56 occupies the neutral position shown in Figure 7, uid from the pump 14. circulates therethrough against the pressure established by the presence of the restricted orice 94, and the valve member 56 remains in balance within its casing 58. It will also benoted that fluid from'the fed pump .44 is discharged through aconduit 96, a conduit 98, a valve passage'or port |00, and a passage |02. At this time a feed pump control valve |04 occupies a position to the right of that shown by the lsolid lines in Figure 7, and thus communication between'the passage |02 and the intake port of the feed pump 44 is established through a port |06 and aconduit |08. Under such cir-- cumstances the feed pump merely circulates without imparting operating fluid pressure tothe ac- Assume that the valve member circuit in Figure 7, I call attention to the circuit disclosed in Figure 9 which is interlocked with the circuit of Figure 7. The circuit disclosed in Figure 9 serves to control the indexing of the work support 40. The shifting of this work support is controlled through the agency of a hydraulic actuator ||0, which includes a cylinder ||2` and apiston H4 reciprocable therein. A piston rod 6 extends fromthe piston ||4 and is provided with rack teeth I8, which are adapted to mesh with companion teeth within a quadrant |20. A control liandle |22 provided at the front side of the machine is adapted to be manually manipulated for initiating a cycle .of operation.

By shifting this control handle to the left, a valve member |24, forming a part of an index control mechanism designated generally by the numeral |26, is moved to the left against the'action of a 4coil spring |28. Fluid from a reservoir |30 is delivered by a gear pump |32 through a conduit `v|34 to a central valve passage or port |36, and thence through a passage or port |38 and a conduit |40 to the right end of the hydraulic actuator cylinder ||2. This causes the piston H4 to move to the left, thereby shifting the work support 40 one-sixth of a revolution, so as to shift a work piece previously applied to the support into position to be acted upon by a set of tools shown in Figure 1.

Fluid from the left end of the cylinder ||2 passes through a conduit |42 and returns through a passage or port |44 in the index control mechanism |26, and from this passage returns through a passage |46 through a return conduit |48 and a restricted orifice |50 into the reservoir |30. pump |32 from any suitable source, such as an electric motor |52.

Attention is now directed to a pair of valve actuating devices |54 and |56, each of which includes a cylinder or casing |58 and plungers or pistons |60. Fluid from the return conduit |42 is also directed at this time into association with the left end of the piston of the mechanism |54 and the right end of the piston in the control mechanism |56. In other words, fluid from the conduit |42 maintains the pistons |60 in the position shown. As the indexing piston ||4 approaches the limit of its stroke to tne left, an arm |62 engages the upper portion of a pivoted finger |64 and thereby releases a valve bar |66. spring |68 then urges the valve bar |66 to the left, and establishes communication between the conduit |40 and a conduit |10 through an anl nular Vvalve port or passage |12. This conduit |10. communicates with the inner extremities of the cylinders |58, and thus the pistons or plungers |60 are urgedoutwardly against the arms |14 and |16 (shown in Figure 7). At this point 1t will be understood that in Figure 1 I have shown only one spindle head. However. in the machine of Figure l two heads are employed, as previously mentioned, and under such circumstances each head is equipped with a main control valve mechvalveV mechanisms and spindle heads are shown.`

Movement of the arm |14 to the left causes 'the valve member 56 to be shifted to its rapid approach position, which would be to the right of Figure 7. 'I'hus it will be apparent that no automatic shifting oi the main control valve member 56 takes place until the indexing of the work support has been completed. A pivoted A coil latch member |18 (Figure 9) cooperates with a latch lug |80 on the control lever mechanism |22 to secure it in its left position againstthe action of the coil spring |28. The latch member |18 is pivoted at |82, and is urged in a clockwise di-,k

rection by a spring |86. A relief valve |86 is provided in the reservoir |30 to take care of any excessive pressures developed by the pump |32,

and suitable check valves |88, |90, and |92 are provided in association with the conduits connected with the cylinder ||2 for purposes which will be apparent as the descriptionv progresses.

The manner in which the valve actuating pistons or plungers |60 act to control the shifting of the main control Valve56 to the rapid approach position will be more apparent from Figure 9.

lt will be seen that the arm |14 is mounted on a vertical shaft |94, the upper end of which carries a handle |96 (Figure 6) to. enable manual remote control. This shaft |96 carries a gear |98, which meshes with a rack in a cross bar 200.

The opposite extremity of this cross bar has a similarfrack, which meshes with a gear 202 mounted Von the vertical shaft 62. .As previously described, thisv shaft 62 carries the iingers 64 and 66.

With the valve member 56 shifted to its rapid approach position, namely, to the right (Figure 7), fluid from the rapid traverse pump I4 passes into the valve housing, and thence outwardly 'through the conduit 98 into the right end of"the actuator cylinder 48. This causes the. head 36 to be moved at a rapid rate toward the work support 88, and uid from the left end of the cylinder 48 passes outwardly through a conduit 204 into a valve passage or port 206, which now communicates with the chamber 88. Thus iiuid is returned through the conduit or pipe line ,92 tothe restricted orice 94 and thence to the reservoir 26. Itwill be observed that the central section of the valve member 56 does not present a complete cylindrical cross-section. Opposite sides of this section are relieved to present areas 208 which permits fluid to pass therethrough. As shown in Figure 7, the upper and lower sections of thecentral portion'of the valve v56 slidably engage the companion surfaces of the bore in the casing 58, while thev oppositely disposed relieved sections 208 of the valve mem- '1 =ber present a passage which permits uid received from the conduit"|8 to pass int'o the valve port 80, and thence into the conduit 98, when the valve member is shifted to its rapid approach position to the right. Likewise, the area 208 fpermits iiuid' received froml the conduit 18 to pass into the valve port 206 when the valve member 56v occupies its left or reverse position.

As the head 36 continues vto advance-at a rapid o rate, the finger 64 (Figure 4) engages the abutment or dog 68, thereby causing the valve member 56' 'to be returnedto its neutral position Vshown in Figure 7. As the valve member 56 i shifts to this position, a sudden building up of pressure is'experienced within the area 200,' and this is transmttedto the right end of the shiftable feed pump control member |04. This causes the member |04 -to be suddenly shifted to the left position shown in Figure 7, thereby connecting 70 the feed pump 44 in a closed circuit with the actuator 46. 'Ihis circuit may be traced as follows: From the feed pump 44 through the conduit 96, the' conduit 98, to the right end of the actuator cylinder 40, from the left end of said cylinder 75 to the conduit 204 into the valve port or passage Y 206 through a passage 2 |0, which now communicates with the central'valve port or chamber |06. This chamber |06 now communicates through the conduit |08 with the intake side of the feed pump 44. It will be seen that the portion of the conduit 98 connected with the valve port |00 is nowclosed by a section 2|2 of the valve member 56. In this manner the head 36 and the head 36a. are advanced at a feeding rate during the cutting action of the tools supported thereby. i

As the heads move-forwardly, a rod 2|4 (Figure 9) carried bythe head 36, and a rod 2|6 carried by the other head, which is fragmentarily shown in Figure 9 and indicated generally by the numeral 36a, eventually engage rollers carried at the opposite extremities of the pivoted latch mexnber |18, thereby releasing the control lever mechanism |22. The spring |28 automatically shifts the lever mechanism |22vto the right, thereby causing fluid from the pump |32 to be delivered to the left end of the actuator. l0 and returning the piston l I8 to the position shown in Figure 9. During this movement, a pawl clicks past the next tooth of a ratchet 2|8 in position to perform an indexing operation upon the return movement of the piston H0. It should also be noted that when the piston ||4 reaches the position shown in Figure 9, fluid entering the left end of the cylinder I0 passes outwardly through the check valve |92 and then through the return conduit |40. As the piston ||4 approaches the position shown in Figure 9, thearm |62 engages a companion arm 220 on the valve bar |66, and shifts said bar sufficiently to reset the latch nger |64, and thereby prevent movement of the bar to the left until the next indexingoperation is completed. As the .tools carried by the heads reach the limit of their cutting stroke,.the right end of a valve member 222 (Figures 4 and 7) engages an abutment or dog 224. Movement of the valve member 222 to the left enables fluid from a left valve chamber 226 to follow through a passage 228, a longitudinal passage 230 within the valve member 222, an annular port 232, and

then through a conduit 234, which makes an unrestricted communication of the, reservoir 16. This sudden release of the iiuid within the chamber 226 enables the valve'member 56 to suddenly.

shift to its left or reverse position. The heads are now'moved at a rapid rate in a reverse direc'- tion. As the heads reach their initial or starting position, the finger 66 engages the abutment or dog 10 (Figure 4), thereby automatically returning the valve member 56 to neutral. .It will be understood, of course, that asimilar set of dogs or ngers is associated with each head. By merely urging lthe lever mechanism |22 to the left, a second cycle of operation is initiated. It will be apparent that after lthe work support has been A Viously described, or-it may be remotely controlled by manipulation of the second handle |96 (Fig- Y ure 3) positioned at the back of the machine.

Attention is now directed to a slow feed mechanism indicated generally by the numeral 238 (Figure 7). This mechanism includesa` casing or housing 240 secured to one side of the head, f

and includes a. shiftable valve mecha-nismllz. This valve-mechanism 242 is comprised of two parts, -namelyl a threaded member 244 and a socket member 246. v'The mechanism 238 is only used in instances where it is desirable to slow down the movement of a head, for example, when it is desired to make a heavier cut. This mechanism 238. serves to divert a predetermined amount of fluid before it is delivered to the actuator cylinder 48, and thereby slow up the movement of the head connected therewith. The operation of the mechanism 238 is as follows: When the head 36 continues to advance through the' feeding stroke, a pivoted arm 248 carried by the mechanism 238 engages an abutment or dog 250. This swings an adjustable screw 252 into engagement with the section 246 of the valve mechanism 242, thereby causing an annular port 254 thereof to register with passages 256 and 258. With the valve member 244 in that position, uid diverted from the conduit 98 through a conduit 268 passes through an adjustable needle valve 262, and thence into the passage 256. The position of this needle valve is controlled through the agency of a coil spring 264 interposed between an adjustable collar 266 and a ange 268. Thus the force tending to close the. needle valve 262 may becontrolled by adjusting the threaded collar 266. Hence, the needle valve can be adjusted so as to open only under a predetermined pressure condition established within the conduit 260. It

will, therefore, be understood that by properly adjusting the needle valve 262, a predetermined amount of fluid may be diverted from the conduit 98 so as to-effect a definite decrease in the rate of movement of the head. As stated above, the slow feed or bleeder valve mechanism 238 is only employed when the natureof the work piece to be machined requires it. A suitable coil spring 210 at the right end of the valve member 244 serves to automatically urge said member to the left when the screw 252 is free to be shifted.

In Figure 8 I have shown a reversing Acontrol mechanism designated generally by the numeral 212, which may be used when occasion demands. This' mechanism includes a valve member 214, which is normally urged to the right into the position shown in Figure 8 by means ofa coil spring 216. When the mechanism 212 is employed, the

conduit or pipe line 234 is not returned directly to the reservoir 16 as shown in Figure '1, but is connected with an opening 218 in the mechanism 212 (Figure 8). Thus, when the valve inemberi214 is positioned as shown, fluid from the conduit 234 A must pass through a restricted annular opening 280 through an outlet port 282, which communicates with a conduit 284, said conduit being con- Y nected with the conduit 92 0f Figure '7. A conduit v286 is connected with the conduit 98 of Figure '1. Hence, when the pressure within the right end Y of the cylinder 48 increases sufficiently to set up pressure within the conduit 98, the valve member 214 shifts to the left against the actionof the Aeven though the valve member 222 has been shifted to the left, the main valve'56 will not shift unless the valve member 214 is open. Hence, a-

delay in the reversal of the actuator takes place, which is dependent upon the time required to build up pressure within the actuator 48.

Referring now to Figures to 14, inclusive. it will be seenA that my invention contemplates the provision of a modified circuit and valve construction, which includes a valve mechanism designated generally by the numeral 290. This mechanism includes a valve casing 292 and a valve member 56a, which valve functions similarly to the valve member previously described. In Figure 10 I have shown a circuit diagram, but have refrained from showing dogs and the like for automatically controlling the functioning of the valve, inasmuch as the same operating mechanism as that previously described in connection with Figures 1 to 9, inclusive, may be employed. A description of the circuit Ashown in Figure 10 can be best understood from a, statement of operation. It will be noted that a. pair of feed pumps, namely, a pump 294 and a pump 296 of larger displacement than the pump 294 are disclosed. These pumps may be constantly driven from a prime mover, as described previously in connection with the pump 44. Fluid from a reservoir 298 is received by a rapid traverse pump 300, and delivered through a conduit 302into a valve port 304. With the valve member 56a occupying the neutral position shown in Figure 10, the fluid circulates through the central valve port 306, a longitudinal passage 308, a valve chamber 310, a'nd a return conduit 3l2 communicating with the reservoir 298 through a restricted orifice 3|4. A feed pump control member l04a, which functions somewhat similar to the member |04 previously described, when occupying the position shown in Figure I0, enables uid from the pump 296 to pass through a valve port 3I6, a passage. 3|8 and thence through a conduit 320, which communicates with a. reversing valve 322. 'Ihe discharge side of the pump 294 also communicates with the reversing valve 322 through a conduit 324. Thus uid from both pumps is adapted to be delivered to the right end of a cylinder 326 of a hydraulic actuator 328 through a eonduit'330. 1 Fluid from the discharge side 0f the actuator 328 passes through a conduit 332, and thence through a conduit 334 into a valve port 336, a passage 338, a

yvalve port 340, and then through a conduit 342,

which communicateswith the intake of both of the pumps 294 and 296. In other words, when the feed control member I04a occupies the position shown in Figure 10, fluid from both pumps is directed to the actuator, thereby causing` said actuator to be propelled at ahigh rate of feed.

Assume that the valve member 56a is now shifted slightly to the left, as shown in Figure 1l, without uncovering the valve ports 336 and 344. Fluid from the valve port 345 flows through a passage 348 into a chamber 350 at the left side of the feed control element or member I04a. With the member I04a in the position shown in Figure 11, uid from the feed pump 296 merely circulates througha conduit 362, the valve port 340, and the conduit 342. The feed -pump 294, however, is adapted to propel the actuator 328 at a slower feeding rate.

56a is shifted to its rapid reverse position, namely, to the left as shown in Figure 12.. 'Ihis causes the member l04a to be shiftedto its right position. In this position uid from the feed pump 296 circulates as described in connection with Figure 11, and iiuid from the pump 294 also circulates by Assume now that the valve member' delivering iiuid from the conduit 324, the conduit l By employing my improved feed pump control ar-` disclosed in Figure 7.

When the valve member 56a is again returned -to neutral/ position, as shown in Figure 14, the

feed pump control element I04a remains in its right position, thereby enabling the slow feed of the actuator'totake place. In order to vshift the control member l04a to the position shown in Figure 10, it is only necessary to shift the valve member 56a to its rapid approach position as shown in Figurev13.

From the foregoing it will be apparent that the control member l04a is adapted to be shiftedv to at least 3 positions, and in each position it serves to control the operative functioning of the feed pumps 294 and 296. Attention is also directed to the provision of bleed passages 364 and, 366, which are employed to take care of any slight leakage in the actuator packings, etc. Also, these bleed passages serve to maintain fluid pressure at the return side f the closed feed circuit.

rangement, a slow or fast feed may be introduced at any instant without the n'c'essity of employing auxiliary devices, such as the common types of load and re arrangements.' By a simple manipulation of the main control valve, the feed control member may be shifted to one of three positions. In one position, namely, the position shown in Figures 10 and 13, both-feed pumps are employed to deliver iiuid'to the actuator, thereby namely, the pump 294, is functionally operative,

the other pump 296 being circulated. In the third position, which I have shown in Figures 12 and 14, the control element serves to circulate both-of the pumps.v This is the positionoccupied when .the machine, 'with which the circuit is employed, is idle. Thus, when the machine is idle, the main control valve 56a occupies the position shown in Figure 14. In this position both the feed and rapid traverse pumps circulate without imparting movement to the actuator. The

reversing valve 322 may be of any suitable design, and may be automatically controlled in response to the movement of a machine element. The valve member 368 shown in Figure 10 is 'similar in functional characteristics to the valve member `222 previously described. AAttention is directed to the fact that a slightly modified arrangement in the form of a needle valve 310 is employed to causea dwell in the reversal of the main valve Figures 15 to 17, inclusive, disclose a pump unit which is particularly adaptable for use in instancesv where the two feed pump arrangement, .'lust'described, is employed. This unit is designated generally by-the numeral 312, and includes a main supporting frame 314. This. frame may be secured as a unit to the side of -a ma'chinebed or the like, which I have designated by the numeral 816 in Figure 16. 'I'he frame 314 serves as a support for the rapid traverse pump 300, the

feed pump 294 andthe feed pump 296. `A drivej shaft 318 delivers power to the pump 296 from a gear 380,l and delivers power to the pump 294 through a similar gear 382. Tha pumps 294 and 296 will not be described in detail in the present application because they'form the subjectmatter of a separate application, and do not form a part of the present application, except as they combine with other elements with which they are associated. It will. suiiice to say that each pump includes a set of valves, namely, anvintake ball valve 384,.which is normally seated through the agency of a coil spring 386, and a discharge ball valve 388, which is normally maintained in its seated position by means of a coil spring 390. The seats of these valves conform with the spherical surfaces of the valves, and function to positively prevent the slippage of fluid from the high complished by turning a shaft 400. The gear 382 also meshes with a gear 402 mounted upon the shaft, which propels the gear pump 300. f

It will also be noted that the frame 314 is arranged to provide a reservoir 404, which is connected through a conduit 406 with the intake side of the gear pump 300. The discharge side of the gear pump 300 connects-with a discharge conduit 1 408. It will thus be apparent that the above described pumping unit presents a self-contained a standard unit and applied to any form of machine wherein the double pump arrangement, as

portable arrangement, which may be produced as above' described, is required. The pumps 294 and 296 may be diierent'ln'displacement, as previously described, or may be identical in size, de-

lpending upon the nature of the work that is to be performed'. In other words, the required feed-` ing rate of travel of the machine will determine the displacement of the pumps to be used.

In Figure 18 a modied circuit arrangement,

very similar in many respects to the circuit described in Figures 10 to 14, inclusive, is disclosed. Instead of employing a three-position feed control member, a two-position feed control member I04c 'isemployed. This member functions identically with the member shown in Figure 7. It will be noted, however, that a modified main control valvev 56e is employed. Particular attentionis directed to an auiliary valve mechanism designated generally by the numeral 410. 'This mechanism includes a casing 4I2, which houses a shiftable valve or control member 414. When the valve member 4I 4 occupies the position shown in Figure 18, uid from the feed pump' 296 is adapted to deliver uid through a conduit 4I6 through a valve port-M8 into a conduit 420, which communicates with a conduit 422 con-` nected with the discharge side'of the pump 294.1

' actuator 928a andthe actuator 328 of Figure 10 resides in the' fact that the actuator 328 employs a shiftable cylinder,V as distinguished from the shiftable piston shown in Figure l0. The actuator arrangement shown in Figure 18 is similar to the actuator arrangement disclosed and described in connection with the circuit of Figure 7, wherein the actuator cylinder is connected directly to the boring machine head.

Attention is directed to the fact that the normal pressure acting within a conduit 424 interposed between the right end of the cylinder 4|2 and a restricted orifice '426, is suicient to maintain the member 4I4 in its left position, in which position the feed pump 296 isadapted to circulate without functioning to propel the actuator. However, when an unbalancing valve 428 (similar to valve 326, Figure 10, and valve 222, Figure-7) is shifted to the right in response to the engagement therewith of a machine part such as the dog 224 (Figures 2 and 4), fluid is free to ow from the right end of the casing 4I2 through the conduit 424, a conduit 430, a chamber 432, a` passage 434, a valve passage 436, and a conduit 438 back into a reservoir 446. The release of the uid from the right end of the valve member 4I4 permits a coil spring 442 to shift said valve member to the position shown in Figure 18. In that position fluid from the'pump 296 is directed by the pipe line 416, the valve passage 4I6, and the conduit 420, through the reverse valve 322er. 'Ihis valve mechanism Aincludes a valvev member 444, and when the valve member occupies the position shown in Figure 18, fluid will pass through a valve port 446 into a conduit 448, which communicates througha piston rod 456 with the right end of an actuator 452 of the actuator mecha` nism 328a. y'I'his causes the actuator cylinder 452 to move to the right and fluid fromthe opposite side of the cylinder will pass outwardly through a channel formed in the opposite section of the piston rod 450 into a conduit 454, and fluid from this conduit passes through the valve 622a and is returned to a port 456 associatedwith the main valve 56o. The valve 56o is now in its rapid reverse position, namely, to the right of the neutral position shown in Figure 18, and .thus return fluid is directed. back through a port 458 in the valve member II14c and a conduit 460 to the intake of the pumps 294 and 296. Thus, it will be apparent that when the parts occupy the foregoing positions, both pumps will be delivering fluid to the actuator' 326a, thereby causing the machine part propelled thereby to move at the faster feeding rate.

It will also be apparent that when the valve 4 I 4 occupies its left position, uid from the pump 296 circulates through the valve port 4 I 8 back through ,the pipe line 466 to the intake of said pump. In other words, when the valve member4 I4 is shifted to its left position, only one of the pumps, namely, the -pump 294, operates to deliver fluid for propelling purposes to the actuator 328a.

The valve member 56o functions in the manner already described in connection with the valve 56 (Figure '7) to control the delivery 4of iiuid from the rapid traverse pump 366 to the actuator 326a. When the valve member 56e occupies the neutral position shown in Figure 18, fluid from the pump 366 circulates through the valve and back to the reservoir 440 through the restricted orifice 426. However, when the valve 56e is shifted to the' left, either manually or in response to the action of dogs as previously described, iiuid from the rapid traverse pump will be directed to one end of the actuator 62811, de- V pending upon the position of the reversing valve 444, and, likewise, when the valve member 56e is shifted to the right in response to theunbalancing of uid produced through the agency of the valve member 428, rapid traverse iiuid may be delivered in a reverse direction to the actuator l Attention is also directed tola hydraulic actuator 462, which includes a cylinder 464 and a numeral 416. This mechanism is shown rather schematically, but enough of the structure thereof is indicated to furnish a clear understanding of the function and purpose of the actuator 462.

It will be notedthat movement of the actuator 462 to the left causes tools 412 mounted in tool holders 414 to move inwardly. This is accomplished through the agency of quadrants 416, which shift inwardly when the lower ends of arms 418 are shifted to the left in response to the movement of the piston rod 468. It will be apparent that the functioning of the actuator 462 is controlled by a valve mechanism 486, which includes a vertically shiftable valve member 482l within a casing 484. Control of the valve member 482 is occasioned by manual manipulation of a suitable handle 486. It will be apparent that as fluid is being discharged from the right side of the actuator cylinder 452 and the valve member 482 is lowered, fluid is introduced through a conduit 486 and thence through a conduit 490 into the right end of the actuator cylinder 464, thereby .causing the piston 466 to be moved to the left,

as described above. Fluid from the advancing side of the piston 466 is passed outwardly through a conduit 492 into the left end o`f the actuator cylinder 452. Inthis manner the tools 412 may be hydraulically urged inwardly at a predetermined rate to perform a facing cut on the work. In order to prevent the building up of undue pressure within the cylinder 464, I provide a conduit 494, which opens when it is. moved into engagement with the adjustable screw abutment 496, Vand thence establishes communication between the opposite 4sides of the pistons 466 and deprives said pistons of any hydraulic motive power. When the'plunger valve 94 opens fluid is free to pass between opposite sides of the piston through a passage 496.

It will be noted that such elements as the hydraulic actuator 321ml and the actuator 462,

' together with the valve'mechanism 480 and the tool operating devices controlled by the actuator piston 466, are all mounted as a unit within a head, which'I have designated generally 'by the numeral 36o. A spindle 5,00 is adapted to be rotated from a prime mover (not shown) mounted upon the head 36o, and this spindle serves to rotate boring tools and the like (not shown). Thus the head is arranged soas to cause a plurality of tools to move in a radial direction, as well as to cause one or more tools to rotate and move in a longitudinal direction. It will also be apparent that the tools 412 may be caused to operate during a dwell of the head 36o so as to perform a facing operation.I In fact, the invention contemplates a diversified application of the structures disclosed in Figure 18. It will also be noted that the reversing valve 444 may be manually controlled through the agency of a handle 562. Obviously the functioning of this valve may also be automatically controlled in response to the movement of the head 36e.

l Referring now to Figure 19, it will be seen that I have disclosed a modified circuit arrangement, which is similar in many respects tothe'circuit disclosed in Figure '1. In orderto more clearly designatethe parts which are similar inboth figures, I have applied like numbers in Figure 19, which bearl the suiiix d. Thus, the circuit in Figure 19 in'ludes' a reservoir 16d, a rapid traverse pump 14d, a main control valve 66d, a feed pump control element I04d, amember 222d for controlling'lthe unbalaneing of the valve member 56d, and a pair of hydraulic actuators 48d and 41d. The circuit also includes a feed pump 44d and a mechanism 238d for controlling thev dwell of the actuator before experiencing reversal. It

lwill be noted that the only material difference between Figure 19 and Figure 7 residesin' the fact that a pair of actuators 46d and 41d are employed, as distinguished from thesingle actul ator 46 in Figure 7. Also, the fluid kdirected to struction itv is preferable' to connect the cylinder 48d directly to the part to be moved, such as the head 36 shown in Figure l. 1 y

It will be noted that fluid from the feed pump 44d passes through a conduit 504 into the right end of 'the actuator 46d. Fluid from the left or discharge end of-the actuator 46d passes through a conduit 506 into the left end of the actuator 41d, and fluid from the discharge side of the actuator 41d passes outwardly through a, conduit 501, and is returned to a valve port 508, a passage 5I0, a port '5I2, and a conduit 5i4 which communicates with the intake side of the pump 44d. In this manner the actuators are conrfected in series within a closed circuit. It will also be noted that when the actuator 41d completes its movement to the left, in response to ,the introduction f iiuid from theV actuator 46d,N

a plunger valve 5|6 engagesanadjustable abutment 5|8. This establishes communication between the opposite sides of the piston 50d within the actuator 41d. Thus-fluid pressure is prevented from being built up within the actuator due to the establishment of communication between the opposite sides thereof. Very accurate `and positive control of avtool or work propelling actuator may be effected by means of the series 'arrangement just described. By employing the plunger valve 5I6, the reversal of the actuators is synchronized. It is apparent that the main control valve 56d controls the travel in both directions oi' the actuators 46d and 41d. By ernploying the control member i04d, it is possible t'o govern the operative functioning of the feed propelling pump 44d without the use of clutch mechanisms and the like, or, in other words., without the necessity of arresting the movement of the pump. That is. to say, the pump may be constantly driven, and, when it is'not needed for purposes, it circulates through the agency of the member |04d as previously described in connection with Figure '1.

In- Figure 20 a modified circuit arrangement is disclosed wherein a feed pump 520 is connected by a conduit 522 with a po'rt 524 at the right side ofV an actuator cylinder 526, and is also connected through a branch conduit 528 with a'port 530 Iat the right end of an actuator/cylinder 532.

l Thus when iluid is delivered to these actuator take of the feed pump 520-through a-conduitv 552.

cylinders by the pump 520, pistons 534 and 536 connectedtogether as a unit by means of a piston rod 538 shift to the left. Fluid from'the advancing Vside of the Apiston 534 is directed through a conduit 540 to one end of a hydraulic actuator 542, and fluid from the advancing vside of the piston 536 is directed through aconduit 544 yto one end of a hydraulic actuator 546.

`This causes pistons 548 and 550, respectively, in

said actuators to be. shifted .to the position shown in Figure y20, andjfluid from the advancingside of said actuators isreturned to the inaoracae Thus the pistons 534 and 536-serve as master controls for the actuators 542 and 546.

A valve member 58e, which is similar in functional characteristics to the valve member 56 shown in Figure 7,` serves to control the opera- 7tive functioning of a rapid traverse pump 554 558 functions to couple a prime mover 560 with a machine tool spindle 562 and the feed pump 520, which is shown somewhat schematically in Figure `20, fluid under high pressure is delivered by the pump 520 to the actuator cylinders 526 and 532 as previously described. When the valve member 56e is shifted toits rapid reverse position, namely, to the right (Figure 20), either by manual manipulation or through the agency of f a member 564 which, serves to control the unbalancing of the valve member 56e, the clutch mechanism 558 is disengaged in response to the actuation of a hydraulic actuator 566. This causes the pump 520 to cease functioning, and fluid from the rapid traverse pump 554 is directed through a conduit 568 to the inner ends of the actuators 542 and 546. Fluid from the advancing side of the actuator piston 548 passes outwardly through the conduit 540 -into a'chamber 510 within the cylinder 526, and uid from the advancing side of the piston 550 passes through a conduit 512 into a chamber 514 within'the cylinder 5,32. In this manner the master pistons 534 and 536 are moved in a reverse direction, and

fluid from theadvancing sides of said pistons is f returned through a conduit 516.

Attention is directed to the fact'that by employing the master cylinder or piston arrangement just described, I am able to use a single pump for producing relatively high pressure in a plurality of cylinders, las distinguished from arrangements wherein`two pumps are employed,

one companion to each cylinder. It will be apparent that the pressure supplied by the pump 520 will be experienced in each of the ports 524 and 530. Thus, if thexpump is developing a pressure of 1,000 pounds, this pressure will be exper1enced by each of the pistons 534 and 536. Un-

der such circumstances the pressures within the chambers 510 and 514 may vary, depending upon the loads experienced by the actuator pistons 54s, and 55e.

It will be apparent that when the actuator pistons 548 and 550 are subjected toa reverse movement, the load distributed within the master" cylinders'526 and 532 will maintain the proper timed movement of the actuator pistons 548 and 550.

That is to say, the actuator piston, which hasA the least load to propel, will furnish the main ,propelling power for the pistons 534 .and 536.

Thus, -uid introduced throughthe conduit 540 to the chamber 510 may impose a predetermined pressure in said chambenand uid through the conduit 544 may be dispatchedat no pressure. In fact, it is possible under` certain circumstances to establish `a vacuum in the chamber 514. In this manner a synchronous movement of the actuator pistons 548 .and 550 is accomplished duringv the reversal thereof.

It will also be apparent that by employing my improved master piston or cylinder construction,`

a desirable compensating pressure arrangement is provided. Assuming, therefore, that 1,000 pounds pressure is applied to the right side of each of the pistons 534 and 538, and that the load experienced by the piston 548 is 500 pounds and the load/experienced by the piston 550 is 1,500 pounds, a

total pressure of 2,000 pounds is available through the agency of the double piston arrangement, although a single pump delivering 1,000 pounds pressure is employed. To further insure the timed reversal of the actuator pistons 548 and 550, I employfplunger valves 518 and 588, as clearly shown in Figure 20.

Referring now to Figure 23, it will be noted that I have disclosed a further modied circuit arrangement. Instead of driving a single pump, such as the pump 520 in Figure 20, I employ a pair of pumps 582 and 584 driven through the agency of the clutch mechanism 558 connected with the prime 'mover 580. The actuator mechanism 588 functions similarly to the mechanism described in Figure 20, and serves to operatively connect the prime mover 580 with the pumps 582 and 584 when it is desired to propel actuators 588 and 588 at a feeding rate. It will be noted that each of the pumps 582 and 584 are connected in a closed circuit with their respective actuators. Each actuator includes a cylinder 598, a piston 592, and piston rods 594. A valve mechanism designated generally by the numeral'588 includes a valve housing 598 and a main control valve member 58j. The valve member 58f functions in the same manner as the valve 58 previously described, in controlling .the delivery of fluid from a rapid traverse pump 808 and in operatively governing the timed functioning of the clutch mechanism 558 which controls the operation of the feed pumps 582 and 584. Therefore, a detailed description of the functioning of the valve member 58j is not believed essential in this connection. Particular attention is directed, however, to a valve mechanism 882, which is shiftable with the valve member 58f. This valve mechanism 802 serves to control the series connection between the cylinders 588 of the actuators 588 and 588. Thus, when the valve member if, and consequently the mechanism or member 802,v are shifted to the left, fluid from the rapid traverse pump 800 passes-through a conduit 804, and thence through a conduit 888 into the right end of the actuator 588. `Fluid from the left end of said actuator passes through a conduit 888, and thence through a port 8m which communicates with a central passage 842. Fluid from the central passage 8|2 (passes through a port 8|4 and a conduit 8I8 into the left end of the actuator 588, and fluid from the right end of the actuator 588 passes through a return conduit 8i8 into a valve .port 820, which is connected with a return conduit 822. This conduit 822 opens into a reservoir 824 through a restricted orifice 828. In the reverse position of -the valve member 58j and the valve mechanism or member 882, fluid is conducted in a reverse direction to the actuators, and in this instance the fluid is directed from the conduit 8|8 through the valve port 8 iii,v and thence outwardly through a valve port which then communicates with the conduit 888.- It will be clear, therefore, that the valve member. or mechanism 802 serves to establish the series connection between the actuators l588 and 588 during the rapid traverse movement thereof. A plunger v828 is employed which en-V gagesan adjustable abutment screw 838. This plunger valve 828 serves as a compensator in timingly controlling the synchronous reversal of the actuator pistons 582.

In connection with the valve members similar tothe valve member 58! previously described, Y I have made reference to a single valve member for eifecting the unbalancing of the main valve in a given direction. In Figure 23 I have shown a pair of control members 832 and 834 which are arranged so as to control the automatic unbalancing of the valve member 58f in either direction. Therefore, when lthe valve member 832 is shifted to the left in response to the engagement therewith of a machine part and the like, uid from an end chamber V838 is free to ilow through the member 832 into a return conduit 838, which has unrestricted communication with the reservoir 824. This effects the sudden shifting of the valve member 58j to the right in response to the Vpressure of the normal balancing uid within an oppositely disposed chamber 840. Likewise, when the valve member 834 is shifted to the right, uid from the chamber 840 is free to flow throughv said member and into the return conduit 838. This causes a sudden shifting of the valve member 58j, and consequentlythe valve member 802, to theleft. Fluid pressure acting within the chambers 838 and 840 is suficlent to normally maintain the valve members 832 and 834 in the position shown in Figure 23. In this position communication between the reservoir 824 and said chambers is closed. A suitable handle 842 is shown which may be manually manipulated to control the shifting of the main valve. ever, automatic control of the valve may be had by employing the dog and slide mechanisms previously described.

In Figure 21 I have disclosed a machine tool designated generally by the numeral 844, which includes a main frame 848 and a pair of arms 848 and 658 pivotally mounted upon shafts 852 and 854, respectively. The portions'of the arms adjacent the shafts 552 and 554 provide tool holders or supports 858 and 858, respectively. Tools 888 and 882 are mounted on said supports and are adapted to operatively engage a rotary work piece 888 when the arms 848 and 858 are swung to the right as shown in Figure 2. These arms are connected through the agency of a link 888. A hydraulic actuator 888 including a cylinder i 810 and a piston 812, connects with the arm 85!)` by means of a piston rod 814. Thus movement of the actuator piston 812 to the right causes the positive and simultaneous movement of the tools 880 and 582 into operative association with the work piece 886. Likewise, the movement of HOW- the piston 812 to the left causes said tools to Y move away from the work piece. The functioning of the tools upon 4the work piece is more clearlyillustrated in Figure 22.

Summary I From the foregoing description it will bei-,apparent that my invention contemplates the `provision of a hydraulic mechanism or system wherein machine tools and the like may be positively and accurately controlled in their forward and reverse movements. Also, my invention contemplates an improved arrangement whereby a predetermined dwell of an actuator during a selected interval of its cycle of operation may be obtained. The multi-feed arrangement incorporates a plurality of feed pumps, which are controlled so that one or all of the pumps may be operatively connected with an actuator whereby to propel said actuator at either a slower or fasterjeeding rate. 'he simple unitary control mechanism for governing the operative functioning of these pumps ohas proven very practical in the field, and precludes the necessity of employing complicated spring and other. type mechanisms for shifting control valves. The pump unit described herein is of practical application in the ileld, because it permits of convenient detachment for purposes of repair, 'replacement,A or removal. In this connection attention is ldirected again to Figures 15 and 16. It will be noted that the entire structure of the pumping mechanisms 296i and 296 is detachably mounted upon thevframe 314and also that the l5 sections294a and 29Go of said pumping mechanisms, which supportthe valve and piston struc` tures, are removable as a unit without requiring the detachment from the frame 314 of the entire pumping structure. `'li'his is of practical signifi- 20 canoe in the eld because it simplifies the manner in which repair, and replacement of pump parts may be accomplished without the necessity of dismantling the entire structure. been the practice in many instances to house the pump structures within an inclcsure illled with oil, thereby making it exceedingly dimcult to gain access to the pump elements. Inmy improved pump unit, all of the elements are exposed for the purpose of rendering the part conveniently removable. My invention also contemplates lmproved means in the form of a'hydr'aullc actuator and associated mechanisms for imparting radial movement to tools supported by a spindle head. This is hydraulically coupled with the main hydraulic actuator in a simple manner. The series and master cylinder arrangements disclosed herein present a practical system of control, which may be used in' instances where the environment is particularly suited to such arrangements.

From the foregoing description it will also be apparent that, by employing the two pump arrangement'each of. said feed pumps may be set to deliver fluid at a predetermined; rate. In other words, one feed pump may be set to deliver fluid atone rate and another feed pump to deliver iluid at a different rate. It is deslrable'in certain instances to set one of the feed pumps to deliver fluid at a given feeding rate and another of said feed pumps to deliver fluid under pressure at a faster/feeding rate. In using the terms feed pump and .rapid traverse pump herein, I am referring to pumps of the "small delivery and large delivery" types, respectively. 'The small delivery type is usually employed to propel machine carriages, spindles, etc., at a slower or feeding rate; while the large delivery pumps are used to propel said machine elements at a faster or rapid traverse rate. Y

Obviously numerous other objects andadvantages are obtained by employing my invention, and it is to be understood that said invention is not limited to the specic disclosures herein, but` Having thus described my invention, what IA claim as new and desire to secureby Letters Patent is:

i. In a hydraulic actuator system, ahydraulic actuator for propelling shiftable supporting parts and the like at a relatively fast rate for bringing said supportingV part intov working position and at a plurality ofrelatively slow rates of travel during the working movement of said part, a plurality of feed pumps, iluid conducting means conaovaeos I Heretofore it has nesting said feed pumps with said actuator, and shiitable means for selectively connecting said feed pumps with said actuator, one ofthe pumps serving and being set to propel the actuator at a4 slower feeding rate, the combined another of said pumps serving and being set to propel the actuator at an increased rate of feed, powern means for propelling said hydraulic actuator at said relatively fast rate of travel, and control means for said power means.

2. In a hydraulic actuator system, a hydraulic actuator for' propelling shiftable supporting parts and the like at a relatively fast rate forv bringing said supporting part into working position and at a' plurality of relatively slow rates of travel during the working movement of said part, a plurality of feed pumps, vuid conducting means adapted to connect said feed pumps' with said actuator, a control valve, and shiftable means operable in response to the shifting of the control valve for selectively connecting said feed pumps with said actuator, one of the pumps serving and .being set to propel the actuator at 4a slower feeding rate, another of said pumps serving and being set to propel the actuator at an increased rate of feed, and power means for propelling said hydraulic actuator at said relatively fast rate of travel. 3. ln a hydraulic actuator and the like at a relatively fast ratev for bringing said supporting part into working position and at a. plurality of relatively slow rates of travel during the working movement of said part, a plurality of feed pumps,

system, a'hydraulic' actuator for propelling shiftable supporting parts uid conducting means adapted to connect saidfeed pumps with said actuator, means for propelling said actuator at 'a rapid rate,l means for controlling the operative functioning of said last mentioned propelling means, shiftable means for selectivelyconnecting one or a plurality of said feed pumps with said actuator, the connection of one pump serving to propel ythe actuator at a relatively slow feeding rate, and the combined pumps serving to propel the actuator at an increased rate of feed, and power means for propelling vsaid hydraulic actuator at said relatively fast rate of travel.-

4. Ina hydraulic actuator system, a hydraulic actuator for propelling shiftable supporting parts and the like at a relatively fast rate for bringing said supporting part into workingpositior and at a plurality of relatively slow rates of travel during the working movement of saldpart, a plurality of feed pumps, fluid conducting means connecting said feed pumps with said actuator, control means for 'said supporting part including a member shiftable to at least two positions for selectively controlling the connection of the pumps with said actuator, said control meansfin one position serving to connect said pumps to propel the actuator at a faster feeding rate, and in another position serving to connect one of said pumps with said actuator to propel the actuator Yat a slower' feeding rate, and serving in one Position to effect the circulation of the iluid delivered by said pumps without imparting movement to the actuator, and power means for propelling said hydraulic actuator at said relatively fast rate of travel.

' 5.V In a hydraulic actuator system, a hydraulic actuator for propelling shiftable supporting parts and thelike, a plurality of feed pumps, fluid conducting means connecting said feed pumps with said actuator, control means for said supporting part including a member shiftable to at least two 

